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从2008-03至2009-02,采用闭合动态法(LI-6400-09)对华西雨屏区不同密度中龄巨桉人工林土壤呼吸进行了研究。结果表明:①该林分土壤呼吸具有明显的季节动态,各密度林分土壤呼吸速率最高值均出现在7月份,最低出现在1月,且密度为883株.hm-2(1.5 m×8 m)的巨桉林土壤呼吸速率最大,2 222株.hm-2(1.5 m×3 m)的最小;②2008年4、7、10月土壤呼吸速率24 h平均值均表现为883株.hm-2>1 333株.hm-2>2 222株.hm-2,且7月>4月>10月;③土壤微生物生物量碳氮、土壤有机质含量和10 cm根系生物量都表现出相同的趋势,即林分密度越小,土壤微生物生物量碳氮越高,草本植物越多,根系生物量越大,有机质含量越多;④温度是巨桉林土壤呼吸变异的主导因子,土壤呼吸速率与土壤温度和湿度的双因素模型优于单因素模型,两者共同解释了土壤呼吸速率月动态的78.3%～91.5%;⑤各密度林分土壤呼吸Q10值随巨桉林分密度增大而降低,大小顺序为3.65(883株.hm-2)>2.60(1 333株.hm-2)>2.55(2 222株.hm-2)。
From 2008-03 to 2009-02, the soil respiration of middle-aged and eucational (Eucalyptus grandis) plantations with different densities in the rain-huging area of Huaxi was studied by closed dynamic method (LI-6400-09). The results showed that: ① The soil respiration of this stand had obvious seasonal dynamics, and the highest values of soil respiration rate occurred in all the stands in July, the lowest appeared in January and the density was 883.hm-2 (1.5 m × 8 m) had the highest soil respiration rate in the Eucalyptus grandis plantation, with the lowest of 222.2 hm-2 (1.5 m × 3 m). ② The average soil respiration rate in April, July and October in 2008 was 883 hhm -2> 1 333 strains.hm-2> 2 222 strains.hm-2, and July> April> October. ③The soil microbial biomass carbon and nitrogen, soil organic matter content and 10 cm root biomass all showed the same The trend was that the smaller the stand density, the higher the soil microbial biomass carbon and nitrogen, the more herbaceous plants, the greater the root biomass, and the more the organic matter content. ④ The temperature was the dominant factor of soil respiration variation in Eucalyptus grandis plantation soil respiration The two-factor model of rate and soil temperature and humidity was superior to the single-factor model, and the two explained 78.3% -91.5% of the monthly dynamic of soil respiration rate. ⑤The Q10 of soil respiration of each density was increased with the density of E. grandis Hm ^ 2)> 2.60 (1 333 strains · hm-2)> 2.55 (2 222 strains · hm-2) with decreasing order of 3.65.